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Title:
METHOD AND DEVICE FOR FORMING A SHAPED GYPSUM PLASTERBOARD
Document Type and Number:
WIPO Patent Application WO/2020/020427
Kind Code:
A1
Abstract:
Method of forming a shaped gypsum plasterboard (22), comprising the steps of: • - arranging a first gypsum plasterboard (10) within a vacuum press (17) and • - pressing and forming the first gypsum plasterboard (10) in the vacuum press (17) to obtain the shaped gypsum plasterboard (22).

Inventors:
BERNETH CLAUS-PETER (DE)
PFANNES ALEXANDER (DE)
Application Number:
PCT/EP2018/000372
Publication Date:
January 30, 2020
Filing Date:
July 25, 2018
Export Citation:
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Assignee:
KNAUF GIPS KG (DE)
International Classes:
B28B1/00; B28B11/10; B29C43/02; B44C5/04; E04C2/04
Foreign References:
GB1375405A1974-11-27
JPS60203404A1985-10-15
EP1389251B12005-11-09
Other References:
None
Download PDF:
Claims:
CLAIMS

1. Method of forming a shaped gypsum plasterboard (22), comprising the steps of:

- arranging a first gypsum plasterboard (10) in a vacuum press (17), wherein the first gypsum plasterboard (10) is wet or wetted; and

- pressing and forming the first gypsum plasterboard (10) in the vacuum press to obtain the shaped gypsum plasterboard (22).

2. The method of claim 1, characterised by:

- providing at least a second gypsum plasterboard (14),

- combining first (10) and the at least one second gypsum plasterboard (14), in particular by an adhesive (13), wherein the at least one second gypsum plasterboard (14) is wet or wetted before or after combining it with the first gypsum plasterboard; and

- pressing and forming first and the at least one second gypsum plasterboard (10, 14) to obtain a laminated shaped gypsum plasterboard (22), wherein the adhesive (13) is preferably, at a beginning of the pressing and forming, in a non-cured state.

3. The method of claim 1 or 2, characterised by the vacuum press (17) comprising a vacuum table (19).

4. The method of one of the preceding claims, characterised by flattening or rounding at least one edge of the first and/or second gypsum plasterboard (10, 14) in the vacuum press (17).

5. The method of one of the preceding claims, characterised by forming at least one two- or one three-dimensional structure, in particular a concave or convex structure, into the first and/or second gypsum plasterboard in the vacuum press (17).

6. The method of one of the preceding claims, characterised by arranging the first and/or second gypsum plasterboard (10, 14) onto a first mold (20) or between a first and second mold or a multitude of molds in the vacuum press (17).

7. The method of claim 6, characterized by an evacuation of the vacuum press (17).

8. The method of one of the preceding claims, characterised by the first (10) and/or second (14) gypsum plasterboard remaining at least 2 min, preferably at least 5 min, further preferably at least 10 min in the evacuated vacuum press (17).

9. The method of one of the preceding claims, characterised by a line on the first (10) or second (14) gypsum plasterboard extending by at least 0.5 % preferably a least 1 % in the vacuum press (17).

10. A device for forming a shaped gypsum plasterboard (22) comprising a vacuum press (17) and at least a first gypsum plasterboard (10).

11. The device of claim 10, characterised by at least a second plasterboard (14).

12. The device of any of the claims 10 or 11, characterised by at least a first mold (20), optionally at least a first and a second mold or a multitude of molds, wherein the first and/or second gypsum plasterboard (10, 14) is/are configured to be arranged on the first mold (20), preferably between the first and second mold.

13. The device of any of the claims 10 to 12, characterised by at least one adhesive (13) for bonding the first and second gypsum plasterboard (10, 14) together and, optionally, a tool for distributing the adhesive (13) on the first and/or second gypsum plasterboard.

14. A use of a vacuum press (17) for forming at least a first gypsum plasterboard (10), preferably for forming a first (10) and at least a second

(14) gypsum plasterboard being arranged on top of each other into a shaped gypsum plasterboard (22).

Description:
METHOD AND DEVICE FOR FORMING A SHAPED GYPSUM PLASTERBOARD

The present invention relates to a method for forming a shaped gypsum plasterboard and a corresponding device.

Gypsum plasterboards are generally known. It is also known to create arched or domed structures from gypsum plasterboards, which can be achieved in several ways. If the plasterboards are thin enough they can be bent in a dry or wetted state creating arched structures. Before wetting the boards the surface lining has to be perforated in order to allow for a uniform access of the water to the liner material and to the gypsum core of the board. After the boards have been wetted they are placed on a forming block and weighed down at its edges in order to allow for a slow deforming process.

This method can be time consuming and it is strongly limited with respect to the bending angle that can be achieved. Thus, mainly large structures with rather small bending angles are produced in this way.

Another possibility to form arched two or three dimensional shapes out of plasterboards is to provide plasterboards which have regularly arranged cut-out regions in which the board material is completely cut through or even removed from one side while the liner material preferably remains untouched on the other side. The cut-out areas provide space around which the board can be bent while the untouched liner provides for cohesion. This method allows for higher bending angles.

However, rather exact handiwork is necessary to produce high quality boards. Additionally, the cut-out boards are very feeble/unstable and difficult to handle during installation. There is always the risk that the liner material along the cut- out regions tears and the board is destroyed. Further, after installation the crevices have to be filled laboriously with joint filler material in order to create a firm structure and to provide a uniform and smooth surface. It is an object of the present invention to provide a method of forming shaped gypsum plasterboards which is variable, simple, and allows for small bending angles. Another object of the invention is a method that allows the production of structures that are smaller than the width of the plasterboard. Moreover, it is an object of the present invention to provide a corresponding device with which the plasterboards are formed.

According to the invention, a method of forming shaped gypsum plasterboards comprises the steps of:

- arranging a first gypsum plasterboard in a vacuum press, wherein the first gypsum plasterboard is wet or wetted; and

- pressing and forming the first gypsum plasterboard in the vacuum press to obtain the shaped gypsum plasterboard.

A core idea of the invention is to use a vacuum press for forming, in particular (two- or three-dimensionally) bending, of the first gypsum plasterboard, in particular a laminated plasterboard comprising a first and/or at least one second plasterboard. This allows a simple two- or three-dimensional molding. The gypsum plasterboard can be molded, for example, in a wavy, convex or concave shape or such that they comprise such a shape within their generally planar bodies.

The method preferably comprises further:

- providing at least asecond gypsum plasterboard;

- combining first and the at least one second gypsum plasterboard, in particular by an adhesive, wherein the at least one second gypsum plasterboard is wet or wetted before or after combining it with the first gypsum plasterboard; and

- pressing and forming first and the at least one second gypsum plasterboard to obtain a laminated shaped gypsum plasterboard. Preferably, before combining or between the combining and the pressing, the second gypsum plaster board is wetted or provided in a wet state. Preferably at the beginning of the pressing and forming, the adhesive is in a non-cured state (e.g. in a liquid state).

The adhesive may be, for example, applied onto the first gypsum plasterboard (e.g. with brush or a notched trowel, e.g. with 0.5 to 1.5 mm, in particular at least approximately 1.0 mm deep notches). When applied onto the first gypsum plasterboard, the adhesive is preferably in a liquid state. Thereafter, the second gypsum plasterboard may be arranged onto the adhesive layer on the first gypsum plasterboard. When the combined (laminated) first and second gypsum plasterboards are arranged in the vacuum press, said adhesive is preferably still liquid. At the end of the pressing and forming step, the adhesive is preferably cured (in particular solid). By combining the first and second gypsum plasterboard, in particular by an adhesive, a reliable and effective forming of the shaped gypsum plasterboard can be achieved.

The vacuum press comprises preferably a vacuum table.

In an embodiment, the vacuum press is a vacuum membrane press (e.g. comprising a table onto which the gypsum plasterboard(s) can be arranged and a membrane part, comprising in particular a frame and a membrane within the frame).

In particular, the vacuum press may use a membrane fitted to a hinged frame attached to a rigid vacuum bed (table) through which the air is removed. By placing the gypsum plasterboards between the membrane and the rigid bed (table), sealing the gypsum plasterboard and then sucking out (most of) the air, a pressure differential is created between the reduced pressure between the membrane and the table and the atmosphere on the outside.

In the vacuum press (during pressing and forming) at least one edge of the first and/or second gypsum plasterboard may be flattened and/or rounded. In particular, during one and the same pressing and forming step, such flattening and/or rounding and molding of a (three-dimensional) shape into the first and/or second gypsum plasterboard can be performed so that a very efficient shaping of the gypsum plasterboards is possible.

In embodiments, at least one two- or one three-dimensional structure can be formed, in particular a concave and/or a convex structure, into the first and/or second gypsum plasterboard (during the pressing and forming in the vacuum press). Such structure may have a wave form (two-dimensional structure) or may be a spherical cap or a segment of a spheroid or any other three-dimensional shape. Further, by applying cuts into the first and/or the second plasterboard also angular shapes can be realized. For example, a triangular flap projecting from the plasterboard area can be formed.

The method preferably comprises further arranging the first and/or second gypsum plasterboard onto a first mold or between a first and at least a second mold in the vacuum press. For example, in a first step, the first mold is arranged within the vacuum press (e.g. on a vacuum table), then in a following step, the first and/or second gypsum plasterboard are arranged on the first mold and, thereafter, optionally a second mold is arranged on the first and/or second gypsum plasterboard with an adhesive in between. Then the vacuum press is evacuated.

Preferably, the first and/or second gypsum plasterboard remains at least two minutes, preferably at least five minutes, further preferably at least 10 minutes in the evacuated vacuum press. The first and/or second gypsum plasterboard may remain less than 40 minutes, preferably less than 25 minutes, even further preferably less than 20 minutes in the vacuum press.

A line on the first or second gypsum plasterboard may extend by at least 0.5% preferably at least 1% in the vacuum press. By a "line" any straight line on the surface of the first or second gypsum plasterboard (in the original state, before the pressing and forming in the vacuum press) should be understood. There is no limit regarding location and extension of such line. According to a further aspect of the invention, a device for forming a shaped gypsum plasterboard comprising a vacuum press and at least a first gypsum plasterboard is proposed. The device may further comprise at least a second plasterboard.

Preferably, the device comprises at least a first mold, further preferably at least a first and a second mold, wherein the first and/or second gypsum plasterboard(s) is/are configured to be arranged on the first mold, preferably between the first and second mold.

The device may comprise at least one adhesive for bonding the first and second gypsum plasterboard together. Optionally, the device may comprise a tool for distributing the adhesive on the first and/or second gypsum plasterboard. Such tool may be, e.g. a notched trowel. Notches of the trowel may have a depth of 0.5 to 2.0 mm, in particular at least approximately 1.0 mm. In an automated manufacture line such a tool may as well be an automatically operated device, for example a roll, capable of applying (liquid) adhesive to the upper surface of the second plasterboard or to the lower side of the first plasterboard.

According to a further aspect of the invention the use of a vacuum press for forming at least a first gypsum plasterboard, preferably for forming a first and at least a second gypsum plasterboard being arranged on top of each into a shaped gypsum plasterboard, is proposed. If two plasterboards are simultaneously formed into one shaped gypsum plasterboard, they can be bonded by a, preferably non-cured, adhesive layer in between of them.

If one or more of the edges of the first and/or second gypsum plasterboard are flattened, the flattened portion may have a width of at least 20 mm, preferably at least 50 mm. In addition or alternatively, the flattened portion may have a depth of at least 1 mm, preferably at least 2 mm and/or not more than 5 mm, preferably not more than 3 mm. Such flattened (edge) portion may ease filling and finishing of the joints of the shaped gypsum plasterboards (without formation of unwanted unevenness) for high surface quality demands. During the pressing and forming step the edges of the first and/or second gypsum plasterboard may be protected by a protecting cover (in particular protecting tissue cover).

After the pressing and forming step, the shaped gypsum plasterboard may be dried and/or cured.

The term "shaped gypsum plasterboard" preferably means a shaped gypsum plasterboard after the pressing and forming step and preferably after a subsequent drying (and curing) step.

It is preferred that the shaped gypsum plasterboard consists of two (laminated) gypsum plasterboards. However, it is also possible that the shaped gypsum plasterboard comprises more than two, for example, at least three or at least four gypsum plasterboards.

A thickness of the first and/or second gypsum plasterboard may be at least 2 mm, preferably at least 5 mm and/or less than 20 mm, preferably less than 10 mm.

The first and/or second gypsum plasterboard each may have one or more gypsum layers. Preferably, the first and/or second gypsum plasterboard comprise at least a facer (paper) layer, in particular a facer (paper) layer and a backer (paper) layer. However, other lining materials as for example (glass fiber) vlies fabric will work as well. Additionally, the invention is also applicable for gypsum fiber boards which usually don't have any lining.

Preferably, a facing side of the second gypsum plasterboard is bonded to a backing side of the first gypsum plasterboard, in particular a facer (paper) layer of the second gypsum plasterboard is bonded with a backer (paper) layer of the first gypsum plasterboard.

The wetting step may comprise applying a liquid by any suitable method, for example by spraying and/or wiping, for example with a piece of tissue. The first and/or second gypsum plasterboard may be (before the forming and pressing step) at least substantially flat (having an at least substantially constant thickness and no recesses or projections, optionally except for the edge portion or one of the edge portions).

The plasterboards used for shaping may be cured plasterboards in which the gypsum contained is hydrated gypsum. However, it is also possible to implement the forming action into the general production process of the plasterboards. The plasterboards may be shaped when the calcium sulfate contained is only partly set and the boards are still in a plastic state, i.e. before being finally cured and dried in a dryer. In this case the plasterboard is inserted into the vacuum press in a wet state and no additional wetting is necessary.

In the following, preferred embodiments of the present invention are described with references to the drawings.

These show:

Fig. 1: A first gypsum plasterboard in a side view;

Fig. 2: The first gypsum plasterboard of Fig. 1 with an adhesive layer;

Fig. 3: The first gypsum plasterboard with the adhesive layer of Fig. 2 and a second gypsum plasterboard;

Fig. 4: The first and second gypsum plasterboard with the adhesive layer together with a vacuum press and a mold;

Fig. 5: The arrangement of Fig. 4 during a pressing and forming step;

Fig. 6: The arrangement of Fig. 4 and 5 after the pressing and forming step;

Fig. 7: A top view of a pressing table of the vacuum press of Figs. 4 to 6 together with the mold.

According to Fig. 1, a first gypsum plasterboard 10 is provided having a first (upper or facing) surface 11 and a second (lower or backing) surface 12. First and second surfaces 11, 12, are (substantially) flat. On the second surface 11, an adhesive layer 13 is applied (see Fig. 2). Thereafter, (see Fig. 3) a second gypsum plasterboard with a first (upper or facing) surface 15 and a second (lower or backing) surface 16 is arranged on the adhesive layer 13 so that the first surface 15 comes into contact with the adhesive layer 13. It is of course also possible to arrange the plasterboards 10, 14 such that they are bonded by their backing sides 12, 16.

A thickness of the first and second gypsum plasterboard may be 3 to 9 mm, in particular (approx.) 6 mm.

According to Fig. 4, the combined (laminated) first and second gypsum plasterboard 10, 14, as shown in Fig. 3, is arranged in a vacuum press 17. The vacuum press 17 comprises a frame 18 (with a membrane) and a table 19. On the table 19, a mold 20 is arranged.

The first and/or the at least one second gypsum plasterboard 10, 14 are wet or wetted before the vacuum press 17 is set into action. The plasterboards 10, 14 can still be wet because they are not yet finally set and cured. It is also possible to wet finally set and cured plasterboards 10, 14 before or after they are placed in the vacuum press 17 and before or after they are combined with one another.

In a following step, the vacuum press 17 is closed, i.e. the frame 18 (with the membrane) is pivoted in the direction of table 19 (as shown in Fig. 5). Moreover, in Fig. 5, a portion of the membrane 21, projecting above the frame 18 can be seen. In the position of Fig. 5, the membrane 21 is (due to evacuation of the space between the membrane and the table 19) in close contact to the gypsum plasterboards 10, 15. By evacuation the membrane presses the plasterboards against the molds and slowly deforms them to conform to the mold's shape.

After a time of stabilisation (e.g. approximately 10 to 20 minutes), the vacuum press is opened again (see Fig. 6). As can be seen in Fig. 6, due to the pressing force of the vacuum press, the mold 20 has molded the (laminated) first and second gypsum plasterboard 10, 14 so that a shaped gypsum plasterboard 22 is obtained. Since the adhesive preferably is not cured when the forming action starts first and second plasterboard can still slide against each other such that there is no strain acting on the adhesive bondage of the finished product. In Fig. 7, a top view of table 19 is shown. In particular, it can be seen that the mold 20 has a circular contour. In three-dimensions, the mold 20 may have a shape of a segment of a sphere or spheroid. In general, more than one, for example at least two or a multitude of molds, such as mold 20, may be arranged on table 19 during pressing and forming. Moreover, one or more further molds may be arranged on top of the second gypsum plasterboard (not shown in the figures) for molding the first and second gypsum plasterboard.

Reference numerals

10 First gypsum plasterboard

11 First side of the first gypsum plasterboard

12 Second side of the first gypsum plasterboard

13 Adhesive layer

14 Second gypsum plasterboard

15 First side of the second gypsum plasterboard

16 Second side of the second gypsum plasterboard

17 Vacuum press

18 Frame

19 Table

20 Mold

21 Membrane

22 Shaped gypsum plasterboard